The present invention relates to therapeutic methods and pharmaceutical compositions employing native hepoxilins and hepoxilin analogs.
Hepoxilins are biologically active hydroxy epoxide derivatives of arachidonic acid formed through the 12-lipoxygenase pathway (Pace-Asciak et al. (1983), J. Biol. Chem., v. 258, pp. 6835-6840; Pace-Asciak et al. (1983), Prostaglandins, v. 25, pp. 79-84; Pace-Asciak et al. (1984), Biochem. Biophys. Acta, v. 793, pp. 485-488). They are formed from 12-HPETE, an unstable hydroperoxide derivative of arachidonic acid (Pace-Asciak et al. (1983), Adv. Prostagi. Throm. Leuk. Res., v. 11, pp. 133-134; Pace-Asciak (1984), J. Biol. Chem., v. 259, pp. 8332-8337). Four natural hepoxilins have been isolated and identified, hepoxilin A3 [8(S,R)-hydroxy-11(S),12(S)-epoxy-eicosa-5Z, 9E, 14Z-trienoic acid] and hepoxilin B3 [10(S,R)hydroxy-11(S), 12(S)-epoxy-eicosa-5Z, 8Z, 14Z-trienoic acid].
These products of an arachidonic acid pathway have been implicated in the mediation of inflammation and smooth muscle contraction by modulation of second messenger calcium response pathways. Hepoxilins have been demonstrated to raise intracellular calcium in human neutrophils in vitro. Hepoxilins have also been demonstrated to be involved in the in vitro release of insulin by pancreatic islet cells (Pace-Asciak et al. (1986), Progr. Lipid Res., v. 25, pp. 625-628), although nothing has been published on the action of hepoxilin analogs on such cells.
U.S. Pat. No. 5,616,607 discloses hepoxilin analogs found to antagonize hepoxilin activity and stated to be useful in the modulation of hepoxilin-mediated processes such as inflammation and in the modulation of other processes mediated by cellular calcium levels. It is suggested that hepoxilin analogs may have utility in diabetes. However, the in vivo activity of hepoxilin analogs has never been demonstrated nor has an increased in vivo efficacy of any hepoxilin analogs been demonstrated with respect to either insulin secretion or the inflammatory process.
In accordance with the present invention, there are provided hepoxilin analogs for use in the regulation of insulin secretion, for the treatment and prevention of both acute and chronic inflammation in a mammal and for decreasing/preventing lung fibrosis in vivo. For the first time it has been demonstrated that certain hepoxilin analogs have a good efficacy or increased potency in mammals in vivo. Native hepoxilin has been referred to herein generally asxe2x80x9cHXxe2x80x9d.
In accordance with one embodiment of the present invention is a method for regulating insulin secretion in a mammal comprising administering an effective amount of a native hepoxilin or hepoxilin analog to said mammal.
According to a further embodiment of the present invention is a method for changing the plasma insulin levels in a mammal, the method comprising administering an effective amount of a native hepoxilin or hepoxilin analog to said mammal.
According to yet another embodiment of the invention is a method for altering plasma glucose levels in a mammal, the method comprising administering an effective amount of a native hepoxilin or hepoxilin analog to said mammal.
The hepoxilin analogs of the present invention also have use in various types of binding assays to identify hepoxilin binding proteins and to identify other forms of such binding proteins as exist for example in diabetes and as such provide a means for diagnosing diabetes in the prediabetic stage. The hepoxilin analogs may also be used in various in vitro assays to study second messenger downstream effects after receptor binding.
In accordance with the present invention are hepoxilin analog photoligands for use in binding studies, most preferably for use in binding studies identifying the hepoxilin binding protein. It is understood by one skilled in the art, that the hepoxilin analogs of the present invention can be chemically modified, for example radioactively labelled as required, for various uses in different assay systems.
The hepoxilin binding proteins have been demonstrated to be G protein coupled as the binding of hepoxilin as well as calcium release is inhibited by non-hydrolyzable analogs of GTP. Additionally, hepoxilin binding causes a rise in cyclic AMP formation indicating that binding is coupled to a Gs-protein. Thus, in accordance with a further embodiment of the invention, is the use of hepoxilin analogs to increase cAMP formation. Hepoxilin and its analogs can be used to elicit second messenger systems via binding to the hepoxilin binding protein.
According to a further embodiment of the invention is a method for treating an inflammatory disorder in a animal comprising administering to the mammal in need of such treatment a therapeutically effective amount of a hepoxilin analog.
According to another embodiment of the invention is a composition for treating an inflammatory disorder in a mammal, the composition comprising a therapeutically effective amount of a hepoxilin analog and a pharmaceutically acceptable carrier.
According to a further embodiment of the invention is a method for treating in a mammal a disorder which involves the development of lung fibrosis, the method comprising administering to the mammal in need of such treatment a therapeutically effective amount of a hepoxilin analog.
According to another embodiment of the invention is a composition for treating a disorder in a mammal which involves the development of lung fibrosis, the composition comprising a therapeutically effective amount of a hepoxilin analog and a pharmaceutically acceptable carrier.
According to a further embodiment of the invention is a method for treating conditions where an anti-coagulative effect is desired, in a mammal, the method comprising administering to the mammal in need of such treatment a therapeutically effective amount of native hepoxilin or a hepoxilin analog.
According to another embodiment of the present invention is a method for modulating vascular tone in a mammal, the method comprising administering to the mammal in need of such treatment a therapeutically effective amount of native hepoxilin or a hepoxilin analog.
According to another embodiment of the present invention is a method for decreasing vascular permeability in a mammal, the method comprising administering to the mammal in need of such treatment a therapeutically effective amount of native hepoxilin or a hepoxilin analog.
According to a further embodiment of the present invention is the use of a native hepoxilin or a hepoxilin analog for decreasing the vascular side effects of chemotherapeutic agents.
According to another embodiment of the invention is a method for reducing or preventing side effects of treatment for malignancy in a mammal wherein the mammal is concurrently receiving a chemotherapeutic agent, the method comprising administering to the mammal in need of such treatment a therapeutically effective amount of a hepoxilin analog and a pharmaceutically acceptable carrier.
According to yet a further embodiment of the present invention is the use of a native hepoxilin or hepoxilin analog for decreasing collagen synthesis associated with tissue fibrosis.